Fuel injection nozzle



March 21, 1961 5 DAHL FUEL. INJECTION NOZZLE 2 Sheets-Sheet 1 Filed Dec. 16, 1957 fnverzfof" Izlnar' .5. flail 3% 5 March 21, 5 DAHL FUEL INJECTION NOZZLE 2 Sheets-Sheet 2 Filed Dec. 16, 1957 fnverzi'or [zlrzar j .Dczkl FUEL INJEC'HUN NOZZLE Einar S. Dahl, Decatur, 1ll., assignor to Borg-Warner Corporation, Chicago, 111., a corporation of Illinois Filed Dec. 16, 1957, Ser. No. 702,853

4 Claims. (Cl. 239-453) This invention relates to fuel injection systems for internal combustion engines and more particularly to a nozzle for injecting fuel into an internal combustion engme.

Fuel injection systems commonly employ a spray type nozzle comprising a nozzle tip having an outwardly flaring opening and a pintle disposed within said tip and adapted to seat against the outwardly flaring opening. The pintle is acted upon by spring means of suflicient force to maintain the pintle seated on the opening except when fuel injection pressure is applied to the pintle. The spring means employed is commonly in the form of a coil spring surrounding the pintle and retained under constant compression by means of a nut threaded on one end of the pintle.

It has been found that, in operation, the pintle is subject to severe vibration requiring that the nut be locked with respect to the pintle or it will be jarred loose therefrom with a consequent release of the compression of the spring.

It has also been discovered in the operation of a fuel injection nozzle that for certain speeds of reciprocation of the pintle corresponding to the revolving speed of the engine, that resonant conditions or standing waves are set up in the fluid conduit supplying fuel to the nozzle. Such resonant conditions severely interfere with the operation of the nozzle and in some cases almost cut off the fuel discharged from the nozzle tip.

It is an object of the present invention to provide an improved fuel injection nozzle having a nozzle tip and a pintle disposed within said tip, and improved spring means for maintaining the pintle seated within the nozzle tip.

It'is still another object to provide a fuel injection nozzle having a fuel discharge opening, a pintle for closing said opening, and adjustable spring means acting on said pintle for calibrating the nozzle so as to open at a predetermined pressure.

It is still another object of the present invention to provide an improved fuel injection nozzle having a nozzle tip with a flared central opening, a pintle disposed within said opening, spring means for maintaining the pintle seated on said opening, and adjustable means for varying the force with which said pintle is seated against said opening.

It is an additional object of the present invention to provide an improved fuel injection nozzle incorporating baflle means therein for reducing the effects of resonant conditions set up in the fuel injection system.

The invention consists of the novel constructions, arrangements, and devices to be hereinafter described and claimed for carrying out the above stated objects and such other objects as will be apparent from the following description of preferred forms of the invention, illustrated with reference to the accompanying drawings, wherein:

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Fig. 1 is a longitudinal sectional view of a nozzle embodying the principles of the present invention;

Fig. 2 is a sectional view taken on line 2--2 of Fig. 1;

Fig. 3 is a view taken on line 33 of Fig. 1;

Fig. 4 is an illustration of the improved nozzle of the present invention as it is located with respect to a cylinder of an internal combustion engine;

Fig. 5 is a longitudinal sectional view of a modified form of the fuel injection nozzle of the present invention;

Fig. 6 is an illustration of a nozzle of Fig. 5 as it is located in a cylinder head of an internal combustion engine.

Like characters of reference designate like parts in the several views.

Referring now to Fig. 1, the illustrated nozzle 10 comprises a nozzle body 11 and a nozzle tip 12. The nozzle tip 12 is in the form of a sleeve and has interconnected longitudinally extending central fuel passages 13 and 14 and an outwardly fiared central opening 15. A pintle 16 extends through the passages 13 and 14 and has a tapered conical head 17 adapted to seat against the flared opening 15. The longitudinal passage 13 is threaded at 1.3a so as to receive a spring retaining sleeve 18 which is threaded therein. The spring retaining sleeve '18 is formed with external threads 18a, a cylindrical central cavity 19 therein and a cylindrical opening 20 in one end thereof through which the pintle 16 loosely extends. A spring 21 surrounds the pintle 16 and is disposed within the cylindrical cavity 19. The spring 21 is disposed under constant compression between a retaining cap 22 mounted on the pintle 16 and one end 23 of the retaining sleeve 18. l

The retaining cap 22 is generally of triangular configuration and has a slotted opening 24 and an enlarged cylindrical cavity 25. The cap 22 is adapted to be attached to the pintle 16 through the opening 24 with the cavity 25 fitting over an enlarged cylindrical end portion 26 formed on the pintle16. Q I

The spring retaining sleeve 18 is formed with a slotted opening 27 extending diametrically through one end thereof. The opening 27 is adapted to receive a tool (not shown) for screwing the sleeve :18 into the nozzle tip 12. r

The nozzle tip 12 is formed with an external'tapered conical surface 28 adjacent to the Iflared opening 15 and terminating therewith at a sharp circular edge'29. The nozzle tip 12 also is formed with a square head 31] adjacent to the tapered surface 23 and adapted to receive a wrench for facilitating assembly of the nozzle 10.

The pintle 16, as shown in Fig. 2, is generally triangular in cross section for a portion of its length the cylindrical passage 14. The triangular portion has peaks or corners 31 in sliding contact with the interior of the passage 14 which function to limit any radical motion of the pintle 16 with respect to the tip 12. The flat sides of the triangular portion of the pintle 16 allow fuel to flow uninhibited to the opening 15.

The nozzle body 11 is in the form of a sleeve and has interconnected longitudinally extending fuel passages 32, 33, 34, 35, and 36 therein. The passages 34,35, and 36 are of successively increasing diameter, and the passage 36 is threaded on its interior and adapted to be screwed on the spring retaining sleeve 18. The nozzle body 11 is formed with an outwardly flared seat 37 at one end of the passage 36 and adapted to seal against a flared mating surface 38 formed on the nozzle tip 12.

The retaining cap 22, as shown in Fig.3, is disposed within the passage 35and has corners or peaks 39 which maintain sliding contact with the interior of the passage 35. The triangular peaks 39 in contact with the passage 35 function to limit the radial motion of the pintle 16,

Patented Mar. 21, 1961 as was previously described for the triangular corners 31 formed on the pintle 16.

The cylindrical passage 32 is threaded on its interior and is adapted to receive a threaded fixture (not shown) attached to a fuel supply conduit.

The cylindrical passage 33 is adapted to receive an annular baffle 40 having a small cylindrical opening 41 therein. The baffle 40 also has a screen strainer 42 enclosed therein for preventing solid particles from entering into the nozzle tip 12. The cylindrical opening 41 has a diameter of approximately of an inch which allows fuel to flow freely therethrough but functions to dampen any vibrations or standing waves set up in the fluid conduit at particular speeds of the internal combustion engine.

The nozzle body 11 is formed with external threads 43 for screwing the nozzle into a threaded opening 44 in the manifold of an internal combustion engine, as shown in Fig. 4.

In assembling the nozzle, the spring retaining sleeve 18 first is threaded Within the nozzle tip 12. Next the pintle 16 is inserted through the opening of the nozzle tip 12 and through the opening 20 in the sleeve 18. The spring 21 then is inserted into the sleeve 18 around the pintle 16. The spring 21 is compressed into the sleeve 18 and the retaining cap 22 is attached to the end of the pintle 16 with the enlarged end portion 26 fitting into the cavity 25. The compression of the spring 21 then is partially released and allowed to act against the retaining cap 22.

. The compression of the spring 21 is adjustable so that the pintle 16 will open for a predetermined fluid pressure within the nozzle 10. This adjustment of the spring 21 is made by fitting a tool (not shown) into the groove 27 and turning the sleeve 18 in one direction or the other relative to nozzle tip'12. After the adjustment of the spring has been made, a drop of sealing compound flows between the threads of the sleeve 18 and the nozzle tip 12, where it hardens after a certain period of time. A type of sealant known as Loclrtite, made by the Correll Engineering Company of St. Louis, Missouri, is particularly useful for this application. The force with which the .pintle 16 seats against the flared opening 15 of the nozzle tip 12 thus is permanently adjusted and the pintle 16 is calibrated so as to become unseated at a predetermined fluid pressure existing within the nozzle 10.

The retaining sleeve 18 next is threaded into the passsage 36 of the nozzle body 11 until the flared opening 37 seals against the tapered surface 38 of the nozzle tip 12. The baflie is inserted into the passage 33 and the nozzle 10 then is completely assembled and ready to be inserted into a threaded opening in the manifold of an internal combustion engine. The only remaining step is to connect the fuel passage 32 of the nozzle 10 to a fluid supply conduit.

Referring now to Fig. 5, there is illustrated a modified form of the nozzle 10 of Fig. l. The nozzle 50 is adapted to be mounted in the cylinder head of an internal combustion engine and to inject fuel directly into the cylinder. As is apparent from the drawing, the nozzle 50 is similar in many respects to the nozzle 10; the pintle 16, the spring retaining sleeve 18, the retaining cap 22, and the bafiie 40 being identical. The internal dimensions of the nozzle 50- also are identical to those of the nozzle 10".

The nozzle 50 comprises a nozzle body 51, a nozzle tip 52, a retaining nut 53, and a spring 54. The spring 54 has a modulus of elasticity that is much higher than that of the spring 21. The nozzle tip 52 has external cylindrical surfaces 55 and 56, and annular surfaces 57, 58, and 59. The surface 57 is adjacent to the flared opening 15 and the surfaces 58 and 59 are adjacent to and on opposite sides of the cylindrical surface 56.

The nozzle tip 52 is adapted to fit into a cylinder head 60 of an internal combustion engine with the surface 57 extending directly into the cylinder. The cylinder head 60 is formed with a cylindrical opening 61 and a coaxial cylindrical cavity 62. The external cylindrical surface 55 of the nozzle tip 52 fits closely within the opening 61. The cylindrical surface 56 fits loosely within the cavity 62 and the surface 58 abuts against a shoulder 63 located between the opening 61 and cavity 62. The cavity 62 is formed with threads 64 throughout a portion of its length and is adapted to receive the threaded retaining nut 53. The nut 53 is threaded within the cavity 62 so that an end 65 thereof abuts against the surface 59 of the nozzle tip 52. The nut 53 compresses the nozzle tip 52 so that an air-tight seal is formed between the annular surface 58 and the shoulder 63. The nut also is formed with a central cylindrical cavity 66 extending throughout its length. The nozzle body 51 extends loosely through the cavity 66 with the flared seat 37 sealed against the tapered surface 38 of the nozzle tip 52.

The nozzle 50 functions in a manner identical to that of the nozzle 10, except that a fuel injection pressure of 400 to 600 pounds per square inch is required for direct cylinder injection as compared to approximately pounds per square inch of pressure for manifold injection.

'Fuel injection pressure for either the nozzle 10 or the nozzle 50 is provided from a timed injection pump (not shown) which transmits fluid under pressure to the cavity 32 in the nozzle body. The baflle 40 with its restricted opening 41 and screen 42 functions to filter the fuel supplied to the nozzle. The screen 42 strains out any foreign solid particles present in the fuel. The restricted opening 41 allows passage of fuel to the nozzle tip, but acts as an impedance to dampen pulsations set up in the fluid supply line due to standing waves or other resonant conditions existing at particular speeds of the vehicle engine.

Fuel injection pressure applied to the nozzles 10 or 50 causes the pintle 16 to lift oif of the tapered seat 15 and allow the passage of fuel into the engine manifold or cylinder. The pintle 16 is unseated from the flared opening 15 at a predetermined pressure. Only a very small clearance is allowed between the flared opening 15 and the tapered head 17. Fuel flowing through this small clearance is atomized so as to leave the nozzle tip 12 in the form of a very fine spray. The fuel spray is mixed with air coming from the intake manifold and is ignited within the cylinder of the vehicle engine in the conventional fashion.

I have provided by this invention an improved fuel injection nozzle which can be easily assembled and permanently adjusted so as to open at a predetermined fuel injection pressure. I also have provided an improved fuel injection nozzle incorporating a bathe effective to dampen pulsations or standing waves due to resonant conditions set up in the fuel injection system.

It is to be understood that my invention is not to be limited to the specific constructions and arrangements shown and described, except only insofar as the claims may be so limited as it will be understood by those skilled in the art that changes may be made without departing from the principles of the invention. 7

I claim:

1. In a fuel injection nozzle for spraying liquid fuel into a chamber in which fuel and air are mixed, the combination of a sleeve-like body member having a longitudinally extending fuel passage therethrough which is threaded on its interior for a portion of its length and to one end of which fuel under pressure is adapted to be supplied, a sleeve-like nozzle tip having a longitudinally extending fuel passage therethrough and forming a fluid tight seal with said body, said nozzle tip being formed with an outwardly flaring opening defining a seat at one end of the fuel passage, a pintle extending into said fuel passage and having a tapered conical head adapted to seal against said seat, a spring for maintaining said pintle against said seat, and a spring retaining sleeve threaded Within said nozzle tip and adapted to adjust the force of said spring and thereby adjust the force acting to hold said pintle against said seat and also adapted to be threaded within said nozzle body so as to attach said nozzle tip to said body.

2. In a fuel injection nozzle for spraying liquid fuel into a chamber in which fuel and air are mixed, the combination of a sleeve-like body member having a longitudinally extending fuel passage therethrough to one end of which fuel under pressure is adapted to be supplied, a sleeve-like nozzle tip having a longitudinally extending fuel passage therethrough and forming a fluid tight seal with said body, said nozzle tip being formed with an outwardly flaring opening defining a seat at one end of the fuel passage, a pintle extending into said fuel passage and having a tapered conical head adapted to seal against said seat, a spring retaining collar fixedly mounted on said pintle, a spring retaining sleeve threaded within said nozzle tip, and a spring disposed under constant compression between said collar and a part of said retaining sleeve, said spring retaining sleeve being adapted to be adjusted longitudinally with respect to said nozzle tip for thereby adjusting the force of compression of said spring and calibrating said nozzle so that said pintle becomes unseated from said seat for a predetermined fluid pressure existing the nozzle.

8. In a fuel injection nozzle for spraying liquid fuel into a chamber in which fuel and air are mixed, the combination of a sleeve-like body member having a longitudinally extending fuel passage therethrough to one end of which fuel under pressure is adapted to be supplied, a sleeve-like nozzle tip having a longitudinally extending fuel passage therethrough and forming a fluid tight seal with said body, said nozzle tip being formed with an outwardly flared opening defining a seat of one end of the fuel passage, a pintle extending into said fuel passage and having a tapered conical head adapted to seal against said seat, a spring retaining cap fixedly mounted on said pintle, a spring retaining sleeve disposed within said nozzle tip,

and a spring disposed under constant compression within said nozzle and acting against said retaining cap, and extending through said sleeve to a remote end thereof and abutting against an inner flange of said sleeve, said sleeve being threaded within said tip and adapted to adjust the force of compression of said spring and thereby calibrate said nozzle so that said pintle becomes unseated from said seat for a predetermined fluid pressure existing within the nozzle.

4. In a fuel injection nozzle for spraying liquid fuel into a chamber in which fuel and air are mixed, the combination of a sleeve-like body member having a longitudinally extending fuel passage therethrough which is threaded on its interior for a portion of its length and to one end of which fuel under pressure is adapted to be supplied and the other end of which is formed with an outwardly flared opening, a sleeve-like nozzle tip having a longitudinally extending fuel passage therethrough and formed with a tapered conical surface adapted to seal against the flared opening of said nozzle body, said nozzle tip also being formed with an outwardly flaring opening defining a seat, a pintle extending through said flared opening and into said fuel passage and having a tapered conical head adapted to seal against said seat, a spring surrounding said pintle and eifective to hold it against said seat, and a spring retaining sleeve threaded within said nozzle tip and adapted to adjust the force of said spring means acting to hold said pintle against said seat, and said spring retaining sleeve also being threaded within said nozzle body and serving as a locking member for holding said nozzle tip in a fluid tight relationship with respect to said nozzle body.

References Cited in the file of this patent UNITED STATES PATENTS 2,531,666 Bower Nov. 28, 1950 2,602,005 Weldy July 1, 1952 FOREIGN PATENTS 618,918 Great Britain Mar. 1, 1949 

